Research group Brunk

Main interests of our group are the functions of the Goa splice variants Go1alpha and Go2alpha in brain and the regulation of vesicular neurotransmitter transporters, especially VMAT2,  by heterotrimeric G-proteins. Mechanisms underlying this regulation were identified by our group. Its physiological relevance was proven for the monoaminergic system. Furthermore we could show influence of Go2alpha on axonal growth.

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The efficacy of synaptic transmission shows short- and long-term variability. One factor which is assumed to contribute to the variability of transmission is the amount of neurotransmitter in synaptic vesicles. The filling of synaptic vesicles are performed by vesicular neurotransmitter transporters, such as the vesicular monoamine transporter 2 (VMAT2) in monoaminergic terminals. The activity of vesicular neurotransmitter transporters is in turn regulated by vesicle-associated heterotrimeric G-proteins. VMAT2 is controlled by the a-subunit of the heterotrimeric G-protein Go2 and the transporter appears to act like a G-protein coupled receptor. In fact, deletion of Go2alpha results in an imbalance of the dopaminergic system. Moreover, studies on Go1alpha deletion mutants indicate that Go2alpha and Go1alpha complementarily affect the monoaminergic system. This suggestion is further supported by the identification of interaction partners of constitutively active Go2alpha. Many of them also interact with Go1alpha in its active or inactive state.

Our group is currently investigating the following aspects:

  • Identification of cytosolic interaction partners of VMAT2
  • Possible direct G-Protein activation by VMAT2
  • Interactions between Go1alpha and Go2alpha and their physiological role in the dopaminergic system

Functions of Go2alpha in the brain

After the identification of different interaction partners of Go2alpha, further analyses revealed that Go2alpha regulates axonal growth. Therefore we are investigating other potential functions of Go2alpha on the development and morphology of neurons in the brain.

Educational research

Knowledge of human anatomy of medical students at German universities

Knowledge of human anatomy of medical students at German universities is discussed controversially. Especially members of surgical disciplines criticize substantial deficits. In cooperation with the group 'Progress Test Medizin', Dieter Scheffner Fachzentrum Charité, knowledge of anatomy was assessed and deficits were confirmed using the students' results from progress testing. The evaluation further revealed that the most difficult aspect (for the students) was  the application of their theoretical knowledge in a clinical setting.

Our current investigations aim at revealing  possible reasons for the deficits in the students' knowledge of human anatomy. To achieve this goal we are also analysing differences between the various curricula here at the Charité.

Funding

DFG-Grant

BR 3937/1-3 Functional characterisation between the vesicular monoamine transporter 2 (VMAT2), the monoaminergic system and the heterotrimeric G proteins Go1 and Go2